// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_
#define BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_

#include <stddef.h>

#include <string>

#include "base/base_export.h"
#include "base/files/file_path.h"
#include "base/macros.h"
#include "base/values.h"

class BASE_EXPORT JSONFileValueSerializer : public base::ValueSerializer {
public:
    // |json_file_path_| is the path of a file that will be destination of the
    // serialization. The serializer will attempt to create the file at the
    // specified location.
    explicit JSONFileValueSerializer(const base::FilePath& json_file_path);

    ~JSONFileValueSerializer() override;

    // DO NOT USE except in unit tests to verify the file was written properly.
    // We should never serialize directly to a file since this will block the
    // thread. Instead, serialize to a string and write to the file you want on
    // the file thread.
    //
    // Attempt to serialize the data structure represented by Value into
    // JSON.  If the return value is true, the result will have been written
    // into the file whose name was passed into the constructor.
    bool Serialize(const base::Value& root) override;

    // Equivalent to Serialize(root) except binary values are omitted from the
    // output.
    bool SerializeAndOmitBinaryValues(const base::Value& root);

private:
    bool SerializeInternal(const base::Value& root, bool omit_binary_values);

    const base::FilePath json_file_path_;

    DISALLOW_IMPLICIT_CONSTRUCTORS(JSONFileValueSerializer);
};

class BASE_EXPORT JSONFileValueDeserializer : public base::ValueDeserializer {
public:
    // |json_file_path_| is the path of a file that will be source of the
    // deserialization. |options| is a bitmask of JSONParserOptions.
    explicit JSONFileValueDeserializer(const base::FilePath& json_file_path,
        int options = 0);

    ~JSONFileValueDeserializer() override;

    // Attempt to deserialize the data structure encoded in the file passed
    // in to the constructor into a structure of Value objects.  If the return
    // value is NULL, and if |error_code| is non-null, |error_code| will
    // contain an integer error code (either JsonFileError or JsonParseError).
    // If |error_message| is non-null, it will be filled in with a formatted
    // error message including the location of the error if appropriate.
    // The caller takes ownership of the returned value.
    std::unique_ptr<base::Value> Deserialize(int* error_code,
        std::string* error_message) override;

    // This enum is designed to safely overlap with JSONReader::JsonParseError.
    enum JsonFileError {
        JSON_NO_ERROR = 0,
        JSON_ACCESS_DENIED = 1000,
        JSON_CANNOT_READ_FILE,
        JSON_FILE_LOCKED,
        JSON_NO_SUCH_FILE
    };

    // File-specific error messages that can be returned.
    static const char kAccessDenied[];
    static const char kCannotReadFile[];
    static const char kFileLocked[];
    static const char kNoSuchFile[];

    // Convert an error code into an error message.  |error_code| is assumed to
    // be a JsonFileError.
    static const char* GetErrorMessageForCode(int error_code);

    // Returns the size (in bytes) of JSON string read from disk in the last
    // successful |Deserialize()| call.
    size_t get_last_read_size() const { return last_read_size_; }

private:
    // A wrapper for ReadFileToString which returns a non-zero JsonFileError if
    // there were file errors.
    int ReadFileToString(std::string* json_string);

    const base::FilePath json_file_path_;
    const int options_;
    size_t last_read_size_;

    DISALLOW_IMPLICIT_CONSTRUCTORS(JSONFileValueDeserializer);
};

#endif // BASE_JSON_JSON_FILE_VALUE_SERIALIZER_H_
